A republic is when power is held by the people and their elected representatives. Rome, on the contrary, was an empire as it continued to expand. An empire is when an extensive group of states are under control by one supreme authority. For example, by 135 BC, during the continuous expansion of Rome, controlled territory had begun to take a toll on the political stability of the Republic. Powerful generals used their influence to build massive personal legions, trading large grants of newly conquered land in exchange for loyalty. Slave uprisings became more frequent as huge areas of territory were converted into farms run almost entirely by slaves. As a result, the Republic became a battleground for the ambitions of some of Rome’s most powerful men.
By 44 BC, Caesar had become the most powerful figure in the Republic and transformed its laws to protect his grip on power. Many senators worried that they would lose their privileges and elite status, or that Caesar would abolish the Republic and declare himself king, or that he might even transfer power to the landless plebeians.
So, led by Gaius Cassius and Marcus Brutus, a group of senators and leading patricians assassinated Caesar, throwing the Republic into another civil war, one from which it would not survive.That's the event that answers your question:
Did one specific event turn Rome into an empireSort of reminds me of what Biden's democrats are trying to do with Trump!!